Aktivität: Vortrag ohne Tagungsband / Vorlesung › Präsentation auf einer wissenschaftlichen Konferenz / Workshop
Structures resembling chlamydospores were observed in 17 out of 100 isolates of P. infestans obtained from potato and other solanaceous hosts occurring in Peru. P. infestans is deemed to not produce chlamydospores, but the structures observed in the isolates have the features known from chlamydospores of other Phytophthora species and, therefore, should be recognized as chlamydospores. The formation of these spores occurred at a low frequency in 16 isolates representing three clonal lineages, and single-zoospore cultures of only one isolate produced abundant chlamydospores. The quantity of spore formation depended on the substrate used for the culture, whereas temperature and lighting had no influence. The conditions required for chlamydospore germination are still elusive. Oospores were formed on old mycelium at a very low frequency by five isolates. Pairing tests with an A1-mating-type crossing partner did not result in oospore formation indicating that all isolates tested belong to the A1 mating type.